1. Technical Field of the Invention
This invention relates generally to timers, and more particularly to an electronic timer apparatus and method incorporating a plurality of predetermined, randomly varying time delay intervals to enable external devices such as lights and televisions to be turned ON and OFF at times which vary controllably and yet in random fashion.
2. Discussion
Electronic timers are used in a wide variety of applications to control the "ON/OFF" operation of electrically powered devices such as lights, televisions, radios, audio equipment, etc. In particular, such timers are frequently employed in residential dwellings to turn ON and OFF lights, televisions, etc. when the occupant is away from the dwelling, such as on vacation. The automatic ON and OFF control of lights, televisions, radios and other like devices can be quite helpful in creating the appearance that the dwelling is still occupied, thus reducing the risk of burglaries, vandalism, and other like events when the occupant is away from the dwelling.
A variety of timers have been developed for controlling the ON/OFF application of electrical power to external devices with the intent of providing as realistic an appearance as possible that a dwelling where such devices are being used within is occupied, while the occupant is in fact absent from the dwelling. Such devices are disclosed in the following U.S. Pat. Nos.:
______________________________________ U.S. Pat. No. Inventor Date Issued ______________________________________ 3,935,404 Persson 1/27/76 4,219,741 Von Gunten 8/26/80 4,570,216 Chan 2/11/86 4,668,878 Wyss 5/26/87 4,695,739 Pierce 9/22/87 4,712,019 Nilssen 12/08/87 ______________________________________
With many prior art timers, a user selects a specific time at which the timer is to couple or uncouple electrical power to an electrically powered device. Accordingly, the electrically powered device is turned ON or OFF at exactly the same time of day every time the apparatus initiates ON or OFF operation of the external device.
In some instances this type of operation may be satisfactory. In many instances, however, it would be extremely desirable to vary, somewhat randomly, the exact time at which such a device initiates ON or OFF operation of an external device. For example, when using electronic timers to turn ON and OFF lights and other appliances in a home while the occupant is away, such as on vacation, it would be extremely desirable if the timer was operable to turn ON and OFF the lights of the home at slightly varying times each day, rather than at the exact same time every day. Since most individuals do not arise or retire at exactly the same time every day, varying the times at which the lights of a house go ON and OFF while the occupant is away further serves to enhance the appearance that the house is occupied and thus reduce the chance of any tampering with the house.
While some prior art timer devices have attempted to provide some degree of random ON/OFF operation of the external devices they control, such timer devices have not operated entirely satisfactory. Problems with sporadic timer operation causing lights and other appliances to be turned ON or OFF at unusual hours of the day or night have limited the efficacy of some prior art timers. Yet another problem with prior art timers has been the inability to provide a user with random, varying time delay intervals which fall within a predetermined range to enable an external device coupled to the timer to be turned ON and OFF at slightly varying (i.e., random) times.
Accordingly, it is a principal object of the present invention to provide an electronic ON/OFF timer apparatus which is operable to apply a plurality of varying time delay intervals to an approximate ON and OFF time as selected by a user, to thereby delay the ON and/or OFF operation of an external device coupled to the timer in accordance with the varying, predetermined time delays.
It is yet another object of the present invention to provide an electronic ON/OFF timer apparatus which provides a means by which an approximate ON and an approximate OFF time can be selected by a user, and which will automatically apply predetermined, varying, time delay intervals each time the approximate ON or OFF time selected by the user is encountered, to thereby provide the appearance of slightly random, varying ON/OFF operation of an external device coupled to the timer.
It is still another object of the present invention to provide a method for controlling the ON/OFF operation of external devices such as lights, televisions, stereo equipment, etc., in accordance with slightly varying, randomly appearing time delays which delay ON and OFF operation of these external devices from approximate ON and OFF times selected by the user.
It is yet a further object of the present invention to provide an electronic ON/OFF timer apparatus which is relatively easy and inexpensive to construct and which couples quickly and conveniently in between an electrical power source and an electrically powered external device.